An important consideration in the design of electronic devices such as, but not limited to, computers, handheld portable devices such as a Personal Digital Assistant (PDA), mobile telephones, etc., is to control the power consumed by a battery contained within the electronic device. By designing electronic devices to have a reduced consumption of battery power by the various components, the usage time per battery charge is extended and the user experience with the device is enhanced. Therefore various components such as, but not limited to, integrated circuits, or portions of circuitry or modules contained on an integrated circuit, may be shut down, or switched into a reduced power mode, during certain instances of operation of the device such that the power consumed by the particular component is reduced.
Memory components present particular difficulties with respect to power reduction in that the memory elements on a device may need to be accessed at any particular time. Therefore if a memory element is placed into a sleep mode, or powered off, time is required and consumed in turning the memory device back on, or pulling it out of the sleep state, in order for read or write operations to resume. As a result of this time delay, applications may experience corresponding time delays and therefore the user experience may be diminished as the user is forced to wait, for example, for applications or displays to refresh or obtain data so that further operation may continue. Additionally, larger memories not only increase power consumption but also generate heat and may thus raise a device's operating temperature.
Therefore a need exists for improved memory devices having reduced battery power consumption.